Particle systems have total energy and distribute energy among particles {statistical mechanics}|.
energy: particle
Particles have energy levels. Particles have possible energy levels. Particle energy level cannot be zero, because particles must move and so have kinetic energy. Particles always have at least minimum ground-state energy, because energy has quanta.
energy: distribution
Some particles have lower energy, and some have higher energy {distribution, energy}. Particles exchange energy by collisions or electronic transitions. Systems have average particle energy, which is higher for higher temperature and/or work. Large systems typically have only one particle-energy distribution, which has highest probability.
energy: total
Sum of particle energies equals total energy. Total energy equals average particle energy times particle number.
energy: types
Particles can have translational energy, vibrational energy, rotational energy, and electronic-transition energy, with different ground states and different quanta. At normal temperatures, vibrational energy is at ground state, electronic-transition energy is at ground state, and rotational energy is above ground state. Total energy distributes equally among possible translation, rotation, vibration, and electronic-transition energy levels, if there are pathways. Systems with large energy quanta have few particles at high-level energies. Systems with small energy quanta have more particles at high-level energies. Energy change does not change particle distribution much.
entropy
Energy distributions have entropy. Entropy change changes particle distribution. Systems with few particles or low temperatures have quantum states, easy transitions among states, and minimal entropy. Systems with many particles or high temperature have thermal states. Black-hole event horizons have random kinetic energy and cause thermal states. Thermal states have random kinetic energy and have maximum entropy.
entropy: degeneracy
Different particle-energy distributions can have same number of particles at each energy level. For example, if two same-type particles exchange energies, system has different particle-energy distribution, same total energy, and same number of particles at each energy level. Different particle-energy distributions with the same energy and same number of particles at each energy level make system phase. System has largest phase, which has highest probability and most even energy distribution possible at total energy. Largest phase has highest entropy.
state: fluctuation
If system is in largest phase, particles have lowest probability of returning to smaller regions, because largest phase has highest probability. If particle collision results in smaller phase, in shortest possible time, system returns to largest phase, because largest phase has highest probability. Hawking radiation requires large phase fluctuation.
Physical Sciences>Physics>Heat>Statistical Mechanics
5-Physics-Heat-Statistical Mechanics
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Date Modified: 2022.0224